Prior to the present invention, one method for making siloxane diols, for example, siloxane bisphenols, were made by effecting reaction between polydiorganosiloxane having terminal silicon hydride siloxy units and a phenol having a nuclear bound aliphatically unsaturated group, such as allylphenol, in the presence of a platinum catalyst. Accordingly, Vaughn, U.S. Pat. No. 3,419,635, assigned to the same assignee as the present invention shows the addition of allylphenol to a polydimethylsiloxane having terminal silicon hydride dimethylsiloxy units. The resulting polydiorganosiloxane having terminal siloxy units with phenol groups attached to silicon by silicon-carbon linkages can thereafter be reacted with phosgene to produce a silicon-polycarbonate block copolymer. if desired, some of these silicone-polycarbonate block copolymers can be used in the preparation of room temperature vulcanizable organopolysiloxane-polycarbonate compositions.
The present invention is based on the discovery that siloxane imide diols having the formula ##STR1## can be used to make siloxane-imide-organic block copolymers having chemically combined polyester or polycarbonate blocks, where R-R.sup.5 are members selected from hydrogen, halogen, C.sub.(1-13) monovalent hydrocarbon radicals and substituted C.sub.(1-13) monovalent hydrocarbon radicals, Z is selected from --O-- and C--(R).sub.2 --, R.sup.6 is selected from C.sub.(1-13) monovalent hydrocarbon radicals and substituted C.sub.(1-13) monovalent hydrocarbon radicals, R.sup.7 is selected from divalent C.sub.(2-13) hydrocarbon radicals and substituted C.sub.(2-13) divalent hydrocarbon radicals, and n is a whole number equal to 1-200 inclusive.